A chroma scaling psychophysics experiment was conducted using a CRT in a dark surround. The experiment consisted of constant hue and lightness IPT step ramps on a uniform background. Each hue step ramp was displayed on an achromatic, a medium and a high chroma background. The results clearly show that chroma scaling is dependent on the chroma of the background. For the medium chroma backgrounds a modest crispening effect is evident. The results also show that chroma scaling on achromatic and high chroma backgrounds differ considerably. The data for the achromatic backgrounds are used to compare C*ab, CIECAM97s C, the revised CIECAM97s chroma, C_F and CIECAM02 C. One phase of the LUTCHI data is also used to verify the results from the visual experiment. CIECAM02 C and C_F both provide good fits to the different data sets relative to C*ab. Furthermore, CIECAM02 C and CF both have considerably smaller intercepts for linear fits of the scale versus the correlate relative to CIECAM97s C.